Fingerprint sensing and matching is a reliable and widely used technique for personal identification or verification. In particular, a common approach to fingerprint identification involves scanning a sample fingerprint or an image thereof and storing the image and/or unique characteristics of the fingerprint image. The characteristics of a sample fingerprint may be compared to information for reference fingerprints already in a database to determine proper identification of a person, such as for verification purposes. AuthenTec, Inc., of Melbourne, Fla., offers a number of particularly advantageous fingerprint sensors under the designation numbers AF-S2, AFS5800, AES4000, AES3400, and AES2500, for example. These integrated circuit fingerprint sensors are also described in U.S. Pat. Nos. 5,963,679 and 6,259,804, for example, and operate based upon electric field sensing and have proven to be very accurate, as well as reliable.
Electronic devices sometimes use menus so that a user may select a menu item from among a plurality of menu items on the menu. More particularly, the menu items may be arranged in a column format so that the user may scroll up or down to select one of the menu items. Other electronic devices include menu items arranged in a plurality of columns so that a user may scroll up, down, or sideways to select a particular menu item. Typically, however, valuable real estate on the housing of the electronic device may be necessary to enable these scrolling and selecting features. In other words, scrolling and selecting features may require multiple switches on the housing.
Some electronic devices use fingerprint sensing applications, as well as a menu scrolling/selection application to allow a user to select a menu item from among a plurality of menu items. These electronic devices, however, may be larger and somewhat bulky due to excess sensing areas and buttons necessary to perform fingerprint sensing, scrolling through a plurality of menu items, and selection of a menu item.
An electronic device disclosed in published U.S. Patent Application Publication No. 2001/0017934 to Paloniemi et al. attempts to account for this problem by providing a sensing data input. The electronic device includes a fingerprint sensor and movement detector that is responsive to movement of the user's skin over the sensor. In other words, the movement detector is responsive to swiping movement of the user's finger over the fingerprint sensor. A fingerprint distortion problem, however, may exist with this type of sensor. Accordingly, the fingerprint sensor may not be able to properly read the user's moving fingerprint, causing delays or errors in selecting a menu item.
Moving finger detection may also require higher power consumption than is desirable by the sensor and by the associated processor that may be internal or external to the sensor. Moving finger gestures may also not be practical in situations where the sensor is mounted in close proximity to other devices, restricting finger motion. The sliding finger motions required by moving finger detection systems may not be easily performed on hand-held devices designed for one-handed operation, such as a cell phone operated by the thumb.
Movement detectors may also be disadvantageous due to excessive power consumption. Further, a movement detector that is responsive to movement of a user's finger may be impractical in situations where the motion detector is mounted in close proximity to other devices. In other words, the finger motion may cause inadvertent activation of other devices in close proximity to the motion detector.